Hi everybody,
I would like to ask to DDCompound if this systems can allow to have very smalls leaks in the bag and not affect the final quality. I mean, if a bag have a very little dispersion of vacuum but i kept it connected to the pump by a digital vacuum switch which restore the original vaccum level, do you think this can produce good quality parts? Of course this cannot be possible by standard infusion without mti…
By the way, can I have some sample too?
Thanks
Well the hose seals up when the resin reaches it, so no. Your best bet is to double bag.
Hanaldo is right. The system has to be tight, even if you use MTI. In some cases it can save your part even if there is a leak, but this is nothing you can be sure.
On critical parts you can double bag, that’s the best way to make sure your bag is tight.
Take a look on our homepage and contact the Italian distributor, he will send you a sample.
I’m in Canada and would like a sample please.Who do I contact?I couldn’t find anything on the web site thanks.
Hello, contact German Advanced Composites. They will send you a sample.
Email sent,thanks
HI DDCompound, i have a very funny issue going on with my MTI hose, does the hose have a shelve life cos whenever i try pulling vacuum it seems like the hose is clogged up with something and im not able to pull any vacuum at all, so far i have cut 3 pieces and they all have the same issue,has any one come across such an issue, what’s going on??? 
Depending on the length of the hose and the degree to with your bag is leaking before fully sealing it off (which, in my experience, is only possible once a somewhat hard vacuum has been applied to figure out where the pinhole leaks in the gum tape are), the MTI hose won’t be able to have any discernible change in the shape of your bag - the pinhole leaks are large enough to replenish the amount of air that a short length of mti hose is able to evacuate.
Best way around this is to clamp your MTI hose line (vacuum vent line) and initially draw down vacuum one your resin inlet line, since it’s usually a wide open port. Once you do this and can confirm that the bag is leak free, then you can worry about whether or not your MTI hose is actually faulty.
One another note of caution that I’ve never seen mentioned here - depending on how…gooey…? your bagging tape is, it is possible for your bagging tape to seep between the seal it’s supposed to create between the MTI hose and your solid vinyl/PET vent line. If there isn’t enough of a length of the MTI’s spiral wrap inside of the solid hose, and enough MTI membrane covering it, then I’ve experienced, on several occasions, that prolonged vacuum before infusion will result in the bag’s pressure forcing the gum tape into the cavity within the MTI hose/vent hose, effectively sealing it. This probable isn’t your problem though since you need prolonged full vacuum for this to happen (has only really occurred when I drop tested for more than a couple of hours).
thanks craj1031tx, this issue is very frustration and i have tried your suggestions, i’ve used MTI hose in the past and i’ve never had such an issue, my part is perfectly bagged and sealed and i have not changed anything on my setup. i just tried the following:
sealed the hose as normal then connected it to the pump without the vacuum bag and as soon as i switch on the pump vacuum is pulled and the gauge reaches the expected reading in seconds which is the same thing which happens when the mold is bagged :(, what on earth is happening please someone come to the rescue cos its very frustrating.
thanks
I think it is like craj said. Maybe the membrane is little less permeable, but we never had that the mebrane is complete sealed.
If you like we change your hose against another charge.
But it is normal that the vacuum pump will be direct near maximum if you use a small piece. It will suck some air, but not as much as the pum can pull, thats why you have direct a vacuum.
Try to preevacuate by the resin feed and than switch to MTI.
You can also make sure that air can pass the membrane by sealing a small piece, place it under water and blow with 1bar into it. Ehen you see bubbles it is air permeable 
I need the help of the infusion gurus of this forum 
I’m using mti hose for some time, i have infused many parts without any problem and the results are perfect.
The last three times i’m dealing with an issue, the first time (i was infusing the bottom part of an airbox) i had a perfect vacuum (no leaks at 40 min drop test), the resin pot 1m below the part and the process was going great. When i saw that the part was saturated with resin i turned off the pump and the vacuum was perfect, after 10-20 minutes i saw the bag became loose instantly (not like it had a small leak but rather had a huge hole), i thought that the problem occurred because i stopped the pump (even though the previous day i infused the upper part of the airbox doing the same steps without any problem). The second time i infused the same part but this time i let the pump running throughout the entire process but the same thing happen, 10-20 minutes after the full saturation of the part the bag became loose. The third time (it was today actually) i infused a hayabusa side panel, again perfect vacuum, no leaks at the 40 minutes drop test, the bag was tight during the infusion the only difference in set up was that i didn’t have the resin pot below the part but i had it above it. Again after 10-20 minutes bag became loose, this time i noticed that the gauge even though the bag was loose it shown -1bar, i isolate the gauge from the pump via a valve but still the gauge shown the same thing, it was like the mti hose was somehow blocked from the rest of the bag and i was seeing the vacuum only inside the mti hose (i hope it makes sense what im’ saying). So i double bagged the part hoping i will salvage the part and the gauge seems to work fine in the second bag, any guesses why this thing is happening.
I apologize for the big post
Your problem is defenitly caused by a leakage. The hose is more or less blocked once it is covered by resin, if there is somewhere now a leak you can not suck out that much air.
It can also be that your tacky tape does not work perfect, once your part is infused there is ambient pressure - height difference in the bag, that is much less than 1 bar difference, so it can be that you tape becomes loose.
i doubt about having a leak, first of all i checked that bag before putting the second on top of it, the tape was intact (envelope bag with only 1m tape in each end) and the “inflation” was to fast for a small leak also the drop test and all the process until that point doesn’t show this. i will use another tape next time though and hopefully the problem will solved.
thanks for the advice
Have you double bagged?
not at first, i never do.
i double bagged when the first bag lost vacuum
Try to double bag direct. Than it will not happen again. I am to 99% sure that it was a leakage.
Sometimes moulds become cracks. Once double bagged that should be tight again.
didnt want to read 50 pages …
is the hose reusable ? i think not ?
The MTI hose is not reusable.
First post, hello all. I was just about ready to purchase my kit, then I read this thread, thanks for rendering my past kit research a waste of time! I’m going to go with the Mti hose method.
I’M requesting a little value add from the manufacturer. (:
Please suggest the best products, that can be purchased in the US, that will aid in simplifying the infusion process as a whole.
Here is my list of products, please anyone, feel free to suggest what I’m missing, better products then listed. Thanks
Robinair 15600 pump (seeking suggestions for what i should add to this pump, valve’s, gauges, etc)
Mti hose
Mti clamps
Needed:
What mold making epoxy putty?
What release films?
What gel coat for easy composite type mold building, plug, gel, and then the epoxy putty?
Best mold release products?
Best flow materials?
Any products that will make the finished side of my piece shin and cut down on finishing labor out of mold, UV protection?
Any other suggestions too help me succeed would be greatly apperciated! Thanks
Just too be clear, I now have nothing, so I want to get started with the right products, and the right company to supply them. My product is a 36" long by 8" wide cylinder that will be made in two parts then glued together (epoxy)
This will be full time manufacturer. So any distributors that want to help me with the right products, and support at my start up level, will benefit once my production ramps up.
Any tricks to hiding the join seams???
Just received a call from them, great info and customer service! Will order these products without doubt. Thanks DD!